Watch crown seal



Jan. 30, 1940. e. MACK WATCH CROWN SEAL Filed D90. 1, 1937 2Sheets-Sheet l [Ml e17 to" ea/7e fo/waml yac Jan. 30, 1940.

G. E MACK 2,188,688

WATCH CROWN SEAL Filed Dec. 1, 1937 2 Sheets-Sheet 2 Patented Jan. 30,1940 eerie WATCH CROWN SEAL George Edward Mack, Truro, Nova Scctia,Canada Application December 1, 1937, Serial No. 177,436

3 Claims.

The principal objects of this invention are to provide an extremelysimple and inexpensive means for sealing the stem or winding arbororifice in watches against the entry of dust or water and. which willautomatically adjust itself to compensate for wear, thereby protectingthe movement from erosive and corrosive elements.

A furtherand important object is to protect the crown stem fromaccidental distortion or breakage and to provide a smooth windingaction.

The principal feature of the invention consists in the provision ofangular contact bearing surfaces on the watch case or pendant and on thecrown and maintaining such surfaces in constant pressure bearing contactthereby providing an effective seal against the ingress of water ordirt.

A further and important feature resides in the novel formation of asealing seat in the watch case of the separable section type withrespective portions of the seat formed in respective sections or thecase and adapted to mate about the crown stem to iormfa peripheralsealing seat when the sections are closed together.

In the accompanying drawings Figure 1 is an enlargedplan View of a watchhaving part of the bezel and cover removed and disclosing a portion ofthe winding and setting mechanism to which my invention is applied.

Figure 2 is an enlarged part sectional elevational view of a portion ofthe structure illustrated in Figure 1 showing the crown in its sealingposition.

Figure 3 is a plan view of the mechanism illustrated inFigure 1 showingthe position of the parts when the crown and stem are moved outwardly inthe setting operation.

Figure 4 is a view similar to Figure 1 of a modified form, of theinvention.

Figure 5 is a side elevational view of the sectional casing on a reducedscale showing the mating portions of the sealing seat formed in therespective portions of the separable casing.

In the manufacture of watches it has been customary to form the case orpendant with a circular orifice through which the crown stem extends,usually in a close turning fit, and in some cases the crown or pendantor both have been formed with bafiie flanges, of more or lesscomplicated and necessarily fragile construction, in an attempt toprevent the ingress of dust but as far as I am aware none of these haveaccomplished the desired result of eifectively sealing the stem orificeagainst the ingress of dust or Water.

The watch mechanism herein shown is that of a well known. type in whicha double springactuated clutch mechanism is mounted on. the crown stem.

The stem 5 is formed with a squared portion upon which the inner clutchor castle wheel 2 is sliclahiy and non-rotatably mounted, the outerratchet face 3 of which engages the winding clutch and the inner ratchetface of which is adapted to engage the setting gear 5.

An annulariy grooved collar 5 is secured upon the stem 5 and the setlever l, which is pivotally mounted on a pin 8 on the movemen frame isprovided with a pin 5 at one end which extends into the groove of thesaid collar so that when the stem is pulled outwardly for setting themovement the lever l is rocked on the pin 8.

The lever '3 is formed with a cam latch H! which operatively engages theshipper I! which is piv- Cit otall'y mounted on the screw 12 andoperatively I engages in the annular groove l3 of the clutch 2 to movesame longitudinally on the stem l to connect the stem with either thewinding or setting clutch.

The shipper spring M is here shown as part of the plate it? and isprovided with a notched end it which engages a pin ll on the outer endof the set lever l and exerts a constant spring pressure on the setlever and through the pin 9 and collar 6 exerts a constant inward springpressure thrust upon the stem I when in the or- 3? dinary or windingposition. The notched end of the spring 64 is adapted to mount the pinI! on the outer end of the set lever when the stem is pulled outwardlyfor setting and temporarily holds the stem in its outward position.

In the structure as illustrated in Figure 4 the shipper arm H pivotallymounted on the screw I2 is engaged by the cam end H) of the set lever Iwhich is pivoted on the fixed pin 8'. The inner end. of the set lever lengages the annular groove in the collar 3 which is fixed on the stem Iso that when the crown 25] is pulled outwardly, this bell crank lever ishifts the shipper arm II to the setting position.

The-lever l is provided with a pin 11 which is engaged by the bevelledsurface l'l of the notched end of the shipper spring l4 and maintains aconstant inward thrust on the spindle I so that the bevelled face of thecrown is maintained in constant pressure contact with the tapered seatin the watch case.

The form of winding and setting mechanism varies considerably indifierent makes of watches but all watches have a structure theequivalent of that described, in that the shipper spring exerts aconstant inward pressure on" the stem holding the winding mechanism ingear therewith.

It is important to note that according to the invention hereincontained, the bevel portion of the crown is so placed that itsengagement with the seat takes place well prior to the return of thestem, shipper spring and set lever to what would otherwise be theirnormal winding position, so that the full co-operation of the shipperspring is obtained in its urge to return to normal or neutral position,thereby definitely ensuring that the bevelled stem and case surfaceswill be maintained in full pressure-sealing contact and providing at thesame time compensation for wear of such surfaces.

As herein shown the case l8, or a pendant when used, is provided with acircular orifice [9 which is bevelled inwardly and presents an angledseat.

The crown 2B, which is suitably secured on the outer end of the stem lis formed with a tapered portion 2|, having the same angle of bevel asthe seat l9, which is adapted, on the inward movement of the stem, toengage the seat l9 and as the shipper spring exerts a constant inwardpressure on the stem the tapered surface of the crown is held in springpressed contact with the tapered seat i9 and forms a dust andwater-tight seal. These closely engaging and concentric surfaces form anaccurate bearing for the spindle so that it will always turn smoothly.

It will also be readily appreciated that the constantly engaging taperof the crown with the taper seat will support the spindle and preventdistortion of the stem in the event of the crown being struck with. anylateral force. Further it will be understood that any wear occurringbetween the tapered surfaces will be automatically taken up by thespring-actuated movement of the stem.

The extreme simplicity of the device will be readily apparent and theinvention can be readily applied to any design of watch.

Another feature of importance is that the taper fit of the crown andseat not only supports the stem but acts as an anchor to hold themovement from shifting in the case.

What I claim as my invention is:

1. In a watch having a bevelled stem orifice in the case, thecombination with the shipper spring and co-operating set lever and stem,said parts having a normal neutral relation with the stem in normalwinding position, of a crown mounted on said stem having a bevelledsurface positioned to sealingly engage the bevelled-stem orifice, all ofsaid parts being so constructed and arranged as to effect said sealingengagement at a point intermediate of the inward travel of the stem tonormal winding position to prevent the full return of said shipperspring and co-operating parts to their normal position, whereby the urgeof the shipper spring to assume normal position is utilized to maintaindefinite pressure-sealing engagement between the respective bevelledsurfaces and compensate for wear therebetween.

2. In a watch having a case formed in separable sections, a crown stemhaving a conically surfaced portion, and spring'means for urging saidcrown s'tem to normal winding position, a conically surfaced seatcomposed of mating portions formed respectively in the'separablesections of the case and so co-operatively related to the aforesaidparts as to effect sealing engagement with said comically surfaced stemportion at such point in the return movement of the stem as to preventits spring-urged displacement to normal winding position.

3. Means as claimed in claim 2 in which said separable casing sectionsare of the type. having overlapping portions with the conical seatportion of one case section underlying the conical seat portion of theother case section in an effective dust-excluding stepped joint.

GEORGE EDWARD MACK.

